Move backgroundColorOf/backgroundColorShouldBe to shadow-dom.js

LayoutTests/fast/dom/shadow/hostcontext-pseudo-class.html

Index: LayoutTests/fast/dom/shadow/hostcontext-pseudo-class.html
diff --git a/LayoutTests/fast/dom/shadow/hostcontext-pseudo-class.html b/LayoutTests/fast/dom/shadow/hostcontext-pseudo-class.html
index e1a0f5fd035c8d39871052ba9a7a9db6763da27a..c770bc1ab08e04a331023ea2b26b02488395b2a2 100644
--- a/LayoutTests/fast/dom/shadow/hostcontext-pseudo-class.html
+++ b/LayoutTests/fast/dom/shadow/hostcontext-pseudo-class.html
@@ -19,14 +19,6 @@ description('Test whether :host-context matches a shadow host correctly.');
 
 var sandbox = document.getElementById('sandbox');
 
-function backgroundColorOf(selector) {
-    return window.getComputedStyle(getNodeInTreeOfTrees(selector)).backgroundColor;
-}
-
-function backgroundColorShouldBe(selector, expected) {
-    shouldBeEqualToString('backgroundColorOf(\'' + selector + '\')', expected);
-}
-
 function cleanUp() {
     sandbox.innerHTML = '';
 }